A year ago, "The Rascal is a small, open-source computer designed for connecting sensors, motors, and whatever else you can build to the internet. It's about 5 cm x 10 cm (2 inches by 4 inches)" would have seemed like a brilliant idea, and it was, but what about now?
My first reaction was they are screwed, this costs $175 and doesn't include Ethernet or video hardware, so whey would anybody in their right mind buy one, when the Pi seems to offer so much more for less cash?
It does, however, have one really, really, powerful ace up its sleeve. It supports the hundreds of Arduino hardware shields that are out there, and that takes it into a completely different arena.
Arduino shields are available for robotics, music, lego, GPS, network, hundreds of applications but the Rascal has considerably more computing power. The Pi won't be able to access this range of hardware for some time yet unless you are prepared to spend time developing the interfaces yourself.
Software wise both the Rascal and the Pi are designed to work with Python,but t he rascal will need a host computer to develop it.
The lower prices of the Pi and Arduino mean a far larger market for hobbyists, the very people who develop open software for free, so the Rascal is going to lag behind, and in some cases you might end up on you own.
18 months ago I might have been tempted, but now its no contest, I have just ordered a third Pi as my first two have proved so useful that they both have full times jobs.
For full details of the Rascal go to http://store.rascalmicro.com/products/rascal-beta-unit